Improvement in adjustable front sights for ordnance



J. B. LEARoCK.'

Sighi'J for Ordnance'l A No. 42,091. Patented Mm1.129,'1864 Unrrnn Sommes PATENT Brien.

JOHN B. LEAROOK, OF BOSTON, MASSACHUSETTS.

IMPROVEMENT IN ADJUSTABLE FRONT SIGHTS FOR ORNANCE.

Specification forming part of Letters Patent No. 42,09l. dated March 29, 1864.

To all whom t may concern:

Be it known that I, JOHN B. LEARocK, a resident of Boston, in the county of Suffolk and State of Massachusetts, have invented an Improved Adjustable Fore Sight for Cannon or Ordnance; and I do hereby declare the same to be fully described in the following specification and represented in the accompanying drawings, of Which- Figure l denotes a front elevation, while Figs. 2 and 3 are vertical sections of it.

The sight as improved by me is to be screwed or otherwise properly ,xed in one ofthe rimbases, or some other proper part of a cannon, it being provided for such purpose with a male screw, a, arrangedatthe base part of its sockettube A. This socket-tube receives a slider, B, on which is markeda scale of divisions, as shown in Fig. l, the socket-tube being provided with a clampscrew, O, which screws laterally into it and against the slider, and serves to maintain the slider at any desirable elevation Within the tube. This slider is not only surmounted by a thin standard, D, having on its upper extremity a small cylinder, E, but is provided With a cylindrical annulus, F, arranged concentrically with the cylinder E, and in other respects as shown in the drawings. The interior surface of this annulus is blackened, or made black or otherwise more or less non-reflective of light, the purpose ofthe annulus being not only to shade the sight-cyl inder E from sun While the cylinder may be in use or in the act of being directed on an object, but to aid in bringing the axis of the cylinder to bear correctly upon the object. The annulus is also advantageous in other respects.

The fore sights of guns or cannon are generally stationary on the piece; or,in other Words, have no means of adjustment, the back sight only being provided with such. In consequence of this, the regulating of the depression of the axis of the gun cannot be effected by the back sight. With my improved gun-sight We have only to raise the sliderin order to enable us to effect the adjustment of the gun for depression-firing. It will be seen,therefore, that my improved gun-sight is especially useful for the barbette and casemate guns of fortresses, as by means of it their depression can be adjusted. It is also useful for other guns, especially when they may be situated on high elevations, where it may be desirable to depress them in order to adjust them to correct firing upon an object.

I claim- The improved'ordnance fore sight, as made with the shade-annulus F, the sight-standard D, and cylinder E, and in other respects so as to be adjustable, substantially as specified.'

' JOHN B. LEAROGK.

Vitnesses:

R. H. EDDY, F. P; HALE, Jr. 

